Continuously-loaded conductor



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r n )MN \N\ QN o m. o o Il ArToRA/Er Patented Apr. 29, 1930 UNITED STATES EAT-ENT OFFICE PAUL Si MCCANN, LA GRANGE, ILLINOIS, ASSIfI-J-NOI,r '.IO VJESTERN ELECTRIGCOM- -j PANY, INCORPORATED, NEW YORK, N. Y., A CORPORATION OF NEW 'YORK coNTINUoUsLY-'LOADED 'connucfron Application mea Juiye, 1927, serial 110,263,732, and infereat Britain muy 22; 192e.

v- This invention relates to loaded conductors and more particularly. to conductors which are continuously loaded with a uniform covering of magnetic material.

Various magnetic materials have been proposed for this purpose, vand they have been wound in the form of wire or tape around a conductor to form a continuous layer. Among the materials proposed are certain alloys which comprise metals of the magnetic group, usually nickel and iron in various proportions, with or without other ingredients. In order to obtain the necessary high permeability in alloys ofthis sort, it has been fourid to be necessary to subject the material to a specific and closely controlled heat treatment after it has been applied to the conductor,

It has been found that when the loading materialv is tight upon the conductor, its permeability after heat treatment is lower than when the material is less tight on the conductor. This effect may be 'due to stresses set-up in the loading material due to the heat treatment. These stresses may be caused by unequal changes in the diameters of the conductor and the loading layer during the heat treatment whereby the loadin material becomes stretched, or they may 'e ascribed to occasional weldings between the conductor and the loading material occurring when these'are in intimate contact during the heat treatment, and giving rise to strains rin the loading material when it is cooled down.

Various methods have been proposedv foil the heat treatment. Other methods consistV in providing a yielding layer between the( conductor and the loading material or in 'de- Vconductor before the l'inal heat treatment and is subjected to a stretching process during or after the heat treatment, whereby the deleterius "interaction between conductor and loadingmaterial may be overcome. The stretching may take place lin whole or in part during the cooling stage of the heat treatment. The conductor may consist of asingle copper Wire,

' or as is more usually the case, may comprise azcentral copper wirearound which are f strained in known manner a plurality of flat vcopper tapes, and the loading material in the form of wire or tape is wound helically about the conductor without special care-tosecure looseness.` `The conductor may be stretched in any desirable manner to secure the necessary loosening of the loading material. Y

The invention will be described in connection ywith theaccompanying drawing in which: y y

' l shows a general arrangement of the apparatus for heat treatingand stretching the loaded conductor;` c

Fig. 2 shows an alternate arrangement of such apparatus; and

Fig' is a more detailed view of agripping device for stretching the conductor.

Referring to Fig. l, 10 and 11 indicate two furnaces which are in juxtaposition. These furnaces may' be of any suitable type and heatedin any desired manner. They are illustrated as being electric furnaces heated by coils diagrammaticall'y shown at 12 and 13,1 respectively. j The furnace 10 is longer than the furnace llrandvisfmaintained at a higher range. .Instead ofV two furnaces, it is to be' understood that a single furnace hav-y struction of the cooling tube reference is made to Patent No. 1,624,668, to F. S. Kochendorfer,rissued April 12, 1927.

rlhev strand 9 to be heat'treated is inthe form of a continuously loaded conductor and is fed from a supply reel (not shown) and proved. l

passedthrough a gripping-device 18, and the tubes 14C-and 15, and a second gripping device 19, and is then taken up on a storage reelY (not shown).

For the sake of simplicity the drawings only illustrate one heating tube and'one cooling tube, hutit is to be understoodthat in practice aV pluralityof tubes similar to the tube lflmay be mounted within the furnaces 10 and 11. and that a plurality of cooling tubes 15l may be utilized therewith. The grippingdevices are designed to receive'a number of strands co responding to the number of cooling tubes.I fBy properly controlf ling the temperature/of the furnacesand the cooling tube as well as the speed with .which the strand progresses therethrough theA elec, trical characteristics of the loaded conductor and particularly the initial permeability of the loadinor material ma be 0'reatl imL b C In oider to .provide both a nonoxidizing .and anon-reducing atmosphere inthe heating tube 14, nitrogen under pressure is forced into the tube through a pipe and in its passage sweeps outl any other gases that may be present inthe tube. Y

The gripping devices 18 and 19 areidentii cal in vconstruction and are designed to firmlyV grip theV conductor 9.v The driving equip' 'ment for the grippingr devices 18 and 19 conT sists of a motor 20, which may be of any suitable typeand a shaft 2.1` suitably journaled in bearings and driven by the motor 20. A setv of gears 22 connectsthe driving shaft 21 with the' gripping device 18 which thereby is driven at a constant predetermined speed. A similar set o-f gears 23 connects the driving shaft 21 to the gripping device 19, the ratio of these gears being such that the device 19 .is driven at a constan-t predetermined speed which'is higher than that of device 18.

AThe construction of the devices 18 and 19 is shown more in detail in Fig. 3 and comprisesa caterpillar mechanism consisting of pair of chains 31 and 32 carrying rubber gripping shoes 37 which are grooved to conform-to the shape of the strand. The chains are mounted within a housing upon sprockets 33,34, vand 36, of which the threef latter are mounted to rotate lfreely upon shafts carried by the housing 30, whereas sprocket 33 is lreyed or otherwise secured to a shaft 41 which is being driven through the set of gearing 22 or 23 shown in Fig. 1 from the motor 20. Secured to the sprocket 35 is a gear 57 which meshes with a similar gear 56 secured to the sprocket 36 for driving the chains 31 and 32 in unison.

rlhe strand 9 enters the housing 30, passes over a suitable stationary shoe 38, then between the rubber shoes 37-37, and leaves through a suitable opening 39 inthe housing. lfhe power supplied from the motor 2O to shaft l1 is transmitted by the sprocket wheel 33 through chain 31 to sprocket wheel 35 andv gear 57, then over gear 56 tosproclretwheel 36, to chain y,32, chains 31 and 32 thus move in unison and'by exerting a tight grip on the ystrand 9 areableto exert a considerable pull on the strand.

To.' vary thepressureof the. shoes 37e-37 upon the strand9, a stationary shoe 58 is suitablymountedbetweenzthe sprockets 33 and35 to engage the inside Vof the `lower run of chain- 31. Adjust-ably mountedlin: a housing 59 is shoe 6() which bears uponthe insideof the upper. run of chain 3-2. rEhe shoe 60 is carried by two cams 61, .each-secured to `a separate shaft 62, journaled'in the housing 59, andA each carrying a ivorrn gear 63 which meshes with worms Ssecured upon ashaft 65, shaft 65 is supported in thehousing 59 and at one endprojects through the housing 30 and on its freeY end carries a crank 66. By turning the crankV one way or-the other the shoe 66 moved vertically upv or down, to vary the pressurevbetiveen the shoes 37-37, and the strand 9 to give: the required traction.

Referring again to` thew general` arrangeH ment shownin Fig.' 1, it is evident. that on account of the tight grip' of the caterpillar 18 on the strand 9, the strand enters :the` furnace 10 witha speedCorrespending to thespe'ed of the 'chains-.in the'v device 18. It is similarly evident that the strand leaves the cooling tube 15 vwith they speed of the cha-ins in theV caterpillar19, which is highe than that of the chains in the-oaterpillar 18. The. strand 9is therefore subjectedto a lengthwise pull between the devices-i118* and 19, vwhichresults in a stretching of the strand.- rllliis*stretching hasbeen found to beeflective toY increase the permeability of the loadingmaterial or' to,

conductor in accordance with this invention may be modified` in accoordancev with that shoivn'infFi'g. 2 in 'which'.tlie partscorrespending4 to those shown in Fig.. 1: are siinilarlyr numbered. The arrangement shown-in y tively, so that the stretching ot the strand 9- cordance- -with this arrangement the gearings 22, 23, and 2e may be dimensioned to impart speeds to the devices 18, 19, and 17, respecmay take place partly between devices 18 and 19 and partly between devices 19 and 17 or may be completely effected at either of these places.` l

The gripping devices 18, 19 and 17 have been described as beingv of the caterpillar type; however, it is possible within the scope ot the invention to attain the desired stretching by the use' of other devices1 known in the art, which will firmly grip the wire and which may be driven at different speeds, it is turthermore not essential to the carrying out or'` the method that the devices 18, 19 and 17 are of similar construction or dimensions. The dilferencein speed imparted to the wire may furthermore be obtained by other means than the sets of gearings described and may be obtained by properly designing the devices 18, 19 and 17.

The method, as described, has a considerable advantage in that the loading material may be kept firmly on the conductor during the handling operations up to the heat treatment so that the conductor may be easily handled without damaging the loading. Moreover7 1n the present process the amount of stretching may be mechanicall determined and-may therefore be both adequate and uniform. A `further advantage of the present process 1s that the loosening of the loading i material may be effected during the drawing of the conductor through the "furnace, and the necessity for a distinct process Jfor this purpose is thus obviated.

1t' it, under certain circumstances, should be round convenient or desirable to carry out the stretching processes after the passage of the conductor through the furnaces, the arrangment shown in Fig. 2 and `described above may be used, or the stretching process may be made a separate loperation after that oi the heat treatment. rlhe loaded conductor is usually found to be in a more suitable condi'- tion for stretching or other deformation after heat treatment than before.

rllhe invention is not limited to the methods and means of loosening the loading mate` rial which have been described. Any known and suitable means may be adapted for this purpose. yEhe conductor may, for'example,

' he rolled down or swaged either during or after the heat treatment to secure looseness or counteract the deleterious effect due to the heat treatment and thereby increase the permeability or the heat treated loaded conductor.

"What is claimed is:

1. A method of improving property of a continuously loaded conductor which has a non-adherent layer of a magnetic alloy about a central conductor which comprises subjecting the vloaded conductor to a heat treatment and elongating the loaded con-` ductor at any time after it enters said heat treatment.

2. A method of vimproving a magnetic Vproperty of a continuously loaded'conductor a magnetic.-

whichhas a layer of magneticmaterial wound upon a central conducting core, which comprises subjecting the loaded conductorto a heating process and then to a cooling process and stretching the loaded conductor at any time after it enters said heat treatment.

3. A continuous method of manufacturing a. loaded conductor which comprises winding the loading material helically upon the conductor, then subjecting the loaded conductor to a heat treatment and elon'ga-ting the loaded conductor at any time after it entersA said heat treatment.

4t. A continuous method of manufacturing a loaded conductor which comprises placing the loading material directly on the conductor, then elongating the loaded conductor y and heat treating the loading material on the conductor during at least part of the elongating process.

5. A method of manufacturing a continuouslv loaded conductor which comprises placing the loading material directly on the conductor, then stretching the conductor and heat treatingv the loading material during at least part of said stretching.

6. A method of loading a signaling conductor with a magnetic material which requires a heat treatment to give it a desired electrical characteristic, which comprises placing a layer of loading material upon the conductor and simultaneously stretching and heat treating said loaded conductor.

7. A method of loading a signaling conductor with magnetic material, which comprises placing a loading material tightly about the conductor, subjecting the loaded conductor to a heating and cooling treatment and stretching the conductor during at least a part of said treatment to prevent deleterious interaction between the conductor and the loading material.

8. A method of producing a continuously loaded conductor which comprises surrounding a conductor with a layer of magnetic material, passing the loaded conductor through a'. heat treating apparatus in such a manner that the speed with which theV conductor leaves said apparatus is higher than that with which it enters.

9. A method of producing a continuously loaded yconductor which comprises surrounding a'conductor with a layer of magnetic material, passing the loaded conductor through a plurality of gripping devices, and through a heat treating apparatus, the passage through at least one of said gripping devices taking place after commencement of the passage through said heat treating apparatus, the speed of one of said devices being higher than that of another of said devices Whereby the loaded conductor is stretched to overcome deleterious interaction between thereon duotor and the loading material.

In Witness whereof, I hereunto subscribe my naine this `lst day of July, A. D.V 1927.

VPAUL S. MCCANN. 

